Pretty much any fan unless it is a "ball bearing" fan is either a sleeve or sleeve like bearing with fluid to assist in that bearing design. Nano can mean fancy coating or fancy plastic, or...?

With that said, I don't find the bearings normally being responsible for the majority of the noise, it's normally the electric motor and fan blade that's responsible for the noise. I do think ball bearing fans can be made with less friction though and the less friction, the less motor power needed and likely less motor noise.

Anyhow, the NB fans are one of the better in noise quality (Smoothness) despite the gimicky "Nano" naming convention.

You could take tap water from Minnesota and call it "Super-Silver-Nano-Sota-Soda-Ultra" and sell it for $10/liter if you put it in a fancy bottle with a purdy label....

 

Is there any validity about sleeve bearings having increased wear due to horizontal mounting? If you were to pick a fan for pulling hot exhaust from a radiator would it be a ball bearing or sleeve bearing fan?

 

I've heard that too, but never really had either one fail on me. I typically run my fans vertically, but I do have some yates in horizontal on my son's build mounted to a rad in the ceiling of the case. It's been running like that for almost a year now no problem and that's a very basic sleeve type bearing. I think some of the FDB and other sleeve like bearings are pretty sealed.

If I had my pick and price was of no concern, I'd probably be running Gentle Typhoon AP14s or 13s or something myself, but I'm cheap and have used yates many times in the past as well and don't really build for show either.

I wouldn't put too much emphasis on the "Horizontal is bad for sleeve bearings" idea, it may have some truth to it, but I've had pretty good luck so far myself and have seen more than one myth in watercooling..